Bottom ring for a hot top



Nov. 14, 1967 D. w. THIEM BOTTOM RING FOR A HOT TOP Filed Nov. 18, 1963INVENTOR. DAROLO w. THIE M LAZO 8 BARRY ATTORNEYS United States Patent3,352,530 BOTTOM RING FOR A HOT TOP Darold W. Thiem, 650 N. SunnyslopeRoad, Elm Grove, Wis. 53122 Filed Nov. 18, 1963, Ser. No. 324,565 2Claims. (Cl. 249202) This invention relates to an improved hot topbottom ring and more particularly to a novel Wiper strip for a bottomring and the method of mounting such a strip on a single-use refractoryring.

This application constitutes an improvement on hot top bottom ringstructures set forth and claimed in co-pending application, Ser. No.108,203, filed May 5, 1961, now Patent No. 3,110,942, assigned to thesame assignee.

The bottom ring structure disclosed in the co-pending applicationutilized a single-use refractory ring either of unitary of sectionalizedconstruction on which a wiper strip had been mounted. The wiper stripincluded an integral wiper blade which projected outward angularly from.the refractory ring to yieldably engage the wall of the associatedingot mold. This blade acted as a seal, in that the molten metal as itrises in the hot top will fill the gap between the hot top and the ingotmold until it comes into contact with the wiper blade. It had been foundthat the molten metal will chill or set when it engages the wiper blade,setting up a seal in the gap around the bottom ring. The wiper blade wasmade of relatively thin metal and at times the molten metal burnedthrough the blade without chilling, resulting in an overflow of theingot molt in the gap between the hot top and the ingot mold moregenerally known as a leaker.

One of the principal objects of the present invention is .to provide animproved Wiper strip for a hot top bottom ring that'reduces thepossibility of overflowing the ingot mold during pouring.

Another object of the present invention is to provide an improved wiperstrip that is readily adaptable to a continuous' method of manufacture.

A- further object is to provide an improved wiper strip 'for a bottomring that will produce a secondary chilling the outer periphery of arefractory ring in a single operation.

A still further object is to provide a hot top bottom ring that can bequickly and easily aligned on the periphery of a refractory ring.

These objects are accomplished by forming a wiper strip from a singlestrip of thin metallic material with a base leg and a side leg whichintersect at an angle corresponding to the angle between the base andside of a refractory ring. The side leg is formed with an integralsection having a crescent or semi-cylindrical shaped or a V or U shapedcross section which extends longitudinally of the side leg intermediateits edges. Groups of slots are provided in the integral section atspaced intervals with a group of notches provided in the base legopposite each group of slots to allow for bending of the wiper striparound the corners of the refractory ring. The wiper strip is mounted onthe refractory ring by wrapping it around the periphery of therefractory ring until its ends overlap. To aid in locating the wiperstrip on the refractory ring a notch may be provided on one side of thering with a corresponding indentation in the wiper strip. When the wiperstrip is aligned with the side and base of the refrac- "ice tory ring,the indentation will seat in the notch preventing any further movementof the wiper strip on the surface of the refractory ring.

The sides of the wiper strip are generally heated and the endsoverlapped and welded together. As the heated sides cool, they willshrink, pulling the wiper strip tightly into position on the refractoryring with the base leg and side leg of the wiper strip matingly engagingthe base and side of the refractory ring, placing the entire ring incompression. When the bottom ring is clipped into position on the bottomof a hot top casing and the hot top placed in an ingot mold, theintegral section will substantially bridge the gap between the bottomring and the surface of the inside wall of the ingot mold. As moltenmetal rises in the gap between the refractory ring and the mold, it willfirst engage the lower portion or wall of the integral section. Achilling effect will be produced in the molten metal which will normallycause it to set, forming a seal. In the event that the molten metal isnot chilled sufiiciently to set, it will burn through the lower portionof the integral section and rise up into engagement with the upperportion or wall of the integral section. A second chilling effect willthen occur which will set the molten metal that has burned through thelower portion or wall. This second chilling eiiect gives additionalassurance that the molten metal will not overflow during the pouringoperation.

Other objects and advantages will become more readily apparent from thefollowing detailed description when read in connection with theaccompanying drawings, in which:

FIG. 1 is a view in perspective of a typical hot top showing the bottomring in partially broken sectional form clipped to a hot top casing.

FIG. 2 is an enlarged sectional view taken on line 2 2 of FIG. 3 showingthe wiper strip offset from a refractory rmg.

FIG. 3 is a view of the bottom ring inverted to show the wiper stripmounted on the refractory ring and aportion of the wiper strip brokenaway to show the locator.

FIG. 4 is a view in perspective of a wiper strip with the integralsection having a crescent-shaped cross section.

FIG. 5 is a view in cross section of a wiper strip' having a V-shapedintegral section.

FIG. 6 is a partial view in cross section showing the .integral sectionof a wiper strip bridging the gap between a hot top is shown having abottom ring lfl mounted on the bottom of a hot top casing 12. Anyconventional means may be used to hold the bottom ring in position onthe hot top casing such as clips 15. The hot top casing shown is ofstandard design having a metal case 14 and a pair of trunnious 16 (onlyone shown) for transporting the hot top in the mill. The inner wall ofthe case is lined with a number of refractory bricks 18 which are heldin position by mortar or cement. This type of hot top casing is shownfor illustrative purposes only since the bottom ring of the presentinvention can be used with any of the known types of casings.

The bottom ring includes a refractory ring 20 which is formed from arefractory material held together with a binder and either baked orbonded together at the manufacturing point. The ring shown is of unitaryconstruction, but may be made from two U-shaped sections or four L-shaped sections depending on the size of the ring. A locating notch 48may be provided in one side of the refractory ring if desired.

A wiper strip 22 is Wrapped around the refractory ring by hand and itsends 24 overlapped slightly so that they can be welded together. Thestrip is formed with a base leg 25 and a side leg 26 with the acuteangle a between these two legs substantially the same as the acute angle11 between the base 27 and side 29 of the refractory ring. An integralsection 28 having a crescent or semi-cylindrical shape (FIG. 2) isprovided on the side leg and projects outward beyond the lower corner 30of the refractory ring.

The wiper strip can be formed by many different methods, but a two-stepoperation is preferred. In the first step, the strip is cutto thedesired length and slotted. The length of the strip will be slightlylonger than the circumference of the refractory ring so that the endscan be overlapped for Welding. Slots 40 and 42 are provided in theintegral section and notches 44 are stamped in the base leg. Slots 40and notches 44 are located at intervals corresponding to the ditsancebetween corners of the refractory ring. Slots 42 are located at thepoints where clips 15 are to be used to hold the bottom ring on the hottop. An indentation or dimple 48 can be pressed into the side leg belowthe integral section in the forming operation at a point equidistantfrom the ends of the strip. In the second step, the wiper strip isplaced in a forming die in order to form the angle betweenthe base legand side leg and the shape of the integral section. With this process ofmanufacturing the wiper strips, they can be stored and shipped instraight or flat sections and mounted on the refractory ring in a singleoperation.

The wiper strip can be mounted on the refractory ring by a singleindividual in one operation by holding the ends of the wiper strip withthe wiper bent in a loop. The wiper strip is then positioned around theouter periphery of the refractory ring with the base leg and side-leg inabutting relation to the base and side of the refractory ring. The endsof the wiper strip are pulled tight until they overlap. The slotted andnotched sections of-the wiper strip are extremely flexible and will bendfreely around the corners of the refractory ring in close engagementtherewith. If the indentation is provided in the wiper strip, it will bealigned with the notch in the refractory ring, positively locating thestrip so that the ends are overlapped at the midpoint on the oppositeside of the refractory ring. This is importhe wiper strip arepulledtightly, overlapped and welded.

As the heated sections of the strip cool, they will shrink, drawing thestrip into tight engagement with the refractory ring. This prestressesthe'ring, increasing its strength considerably as more completelydescribed in the co-pending application.

Referring to FIGS. 6 and 7 a broken sectional view of 4 the bottom ringand wall of an ingot mold is shown. The integral section 28 will engagethe wall of the ingot mold or be spaced slightly away from the wall,leaving a small gap. If the wiper ring is squeezed between the ingotmold and the bottom, it is sufiiciently flexible so that it will notbreak off. In FIG. 6, the molten metal is shown in engagement with thelower wall 32 of the formed section. The molten metal will melt thewiper strip, but the metal in the strip will normally produce a chilleffect in the molten metal that causes the outer skin 50 of the moltenmetal to set, sealing the gap. If the heat of the molten metal burnsthrough the outer skin of set steel, it will rise up into engagementwith the second wall 34 (FIG; 7) where a secondary chill-effect occurs.Since the exposed surface of the rising molten metal has alreadyundergone a primary chilling effect at the lower wall, the upper wallwill cause a second chill effect that guarantees that the metal willset. 1

The same effect will be produced'by a V-shaped integral section 36 asshown in FIG. 5. The lower wall 38 of the V-shaped section will beengaged by the molten metal pro-'- ducing the initial chill effect. Ifthe molten metal'burns through the lower portion, it will engage the'upper'wall 39 which produces the secondary chill effect. Any wiperstrip cross section such as a V or U which places two walls in the pathof the molten metal in sequence will provide the desired effect.

Although only a few embodiments of the present invention have been shownand described, it should be apparent that various changes andmodifications can be made without departing from the scope of theappended claims.

I claim:

1. A wiper strip for a refractory ring, the combination thereof forminga bottom ring for a hot top used in pouring molten metal in an ingotmold, comprising a strip of metal having a base leg and an edge leg,said'edge leg having a multi-walled section integral therewithand'forming a continuation along the full length of the wiper strip forproducing a first chill effect when engaged by-molten metal rising inthe ingot mold and a second chill effect in the event that the moltenmetal burns through the'first wall.

2. A wiper strip according to claim 1 wherein said multiwalled sectionhas a first metal wall and a second metal wall positioned in the gapbetween the bottom ring and ingot mold, whereby molten metal rising inthe gap will engage said walls sequentially.

References Cited UNITED STATES PATENTS 3,058,182 10/1962 Urmetz et a1.249-.202 3,110,942 10/1963 Thiem et al. 164-6 I. SPENCER OVERHOLSER,Primary Examiner. R. D. BALDWIN, Assistant Examiner,

1. WIPER STRIP FOR A REFRACTORY RING, THE COMBINATION THEREOF FORMING ABOTTOM RING FOR A HOT TOP USED IN POURING MOLTEN METAL IN AN INGOT MOLD,COMPRISING A STRIP OF METAL HAVING A BASE LEG AND AN EDGE LEG, SAID EDGELEG HAVING A MULTI-WALLED SECTION INTEGRAL THEREWITH AND FORMING ACONTINUATION ALONG THE FULL LENGTH OF THE WIPER STRIP FOR PRODUCING AFIRST CHILL EFFECT WHEN ENGAGED BY MOLTEN METAL RISING IN THE INGOT MOLDAND A SECOND CHILL EFFECT IN THE EVENT THAT THE MOLTEN METAL BURNSTHROUGH THE FIRST WALL.